Tropical Journal of Pharmaceutical Research, June 2008; 7 (2): Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria. All rights reserved. Research Article Available online at Antifungal activity of Erigeron floribundus (Asteraceae) from Côte d Ivoire, West Africa FH Tra Bi. 1*, MW Koné 1, NF Kouamé. 2 1 UFR Sciences de la Nature, Université d Abobo-Adjamé, 02 BP 801 Abidjan 02,Côte d Ivoire. 2 UFR Biosciences, Université de Cocody-Abidjan, 22 BP 582 Abidjan 22, Côte d Ivoire Abstract Purpose: Erigeron floribundus is a reputed medicinal plant used in Côte d Ivoire, West Africa for the treatment of skin disorders. The aim of this study was to evaluate the antifungal activity of this plant against fungi from human origin. Method: Dichloromethane, methanol 80% and aqueous extracts from the leaves with stem were tested for their antifungal activity against 7 strains of dermatophytes (Epidermophyton floccosum, Microsporum canis, M. gypseum, M. langeronii, Trichophyton mentagrophytes, T. rubrum, T. soudanense) and one strain of the filamentous fungus, Scopulariopsis brevicaulis. The assays were performed using the agar dilution method at serial concentrations ranging from 2 to 0.06 mg/ml. Result: Only the dichloromethane extract exhibited an activity against Microsporum canis and a broad spectrum of good antifungal activity against all the remaining fungi tested. Conclusion: To the best our knowledge, this is the first report of the antifungal activity of Erigeron floribundus against a wide range of dermatophytes, including Microsporum langeronii and Trichophyton soudanense, the most frequent dermatophytes in Côte d Ivoire. E. floribundus might be potential sources for improved traditional medicines or new antidermatophyte agents for the treatment of dermatomycoses. Keywords: Erigeron floribundus, dermatophytes, antifungal activity, Côte d Ivoire. *Corresponding author: Tel : (+225) Trop J Pharm Res, June 2008; 7 (2) INTRODUCTION Dermatophytes are fungi that can cause infections of the skin, hair, and nails due to their ability to utilize keratin. The organisms are transmitted by either direct contact with infected host (human or animal) or by direct or indirect contact with infected exfoliated skin or hair. The most common clinical manifestations are beard, glabous skin, scalp, groin, hand, feet, and nails. These infections, which constitute the most frequent fungal diseases in human 1, are widespread in tropical countries. Dermatomycoses due to Epidermophyton floccosum, Microsporum gypseum, Trichophyton mentagrophytes and T. rubrum are commonly worldwide. Dermatoses caused by Trichophyton soudanense are limited to Africa. For instance, tinea capitis are endemic problem in Africa where they constitute a serious public health problem, particularly in children 2 and immunodeficient patients 3,4. In Côte d Ivoire, the most frequent etiologic agents in school children are Microsporum langeronii and Trichophyton soudanense that infect scalp and hair 5. Despite the existence of antifungal agents effective on dermatophytes, there is a need to search for alternatives. The relative high cost and constraints due to the length of the modern treatment curb the control of the dermatomycoses in developing countries like Côte d Ivoire. Patients, in particular, the resource-poor people from remote areas still use traditional medicine for the treatment of various diseases from microbial and non microbial origin 6, 7. So people know a lot about medicinal plants that can cure diseases of the skin, hair and nails. One of such plants is Erigeron floribundus (Kunth) Sch. Beep. (Asteraceae) known as a reputed medicinal plant traditionally used for the treatment of skin disorders by the rural populace as well as those from the urban areas of Côte d Ivoire 8. This species is widespread in Africa. The present study investigates the effects of E. floribundus against fungi from human origin. 976 EXPERIMENTAL Plant material E. floribundus is an herbaceous plant growing in tropical areas and can reach 2 m. This species belongs to the family of Asteraceae. The leaf is simple, linear, pubescent and dentate. The inflorescences are yellow panicles. Fruits are dry indehiscent. The plant material (leaves) was harvested in July 2005 in Abidjan (Southern Côte d Ivoire). Samples were identified at the herbarium of Botanical Garden (University of Cocody- Abidjan) where voucher specimens (375 TB) were deposited. The botanical nomenclature of Hutchinson and Dalziel 9 as revised by Lebrun and Stork 10, 11 was adopted to name the species. Preparation of plant extracts Powdered portions of the plant material (100 g) were successively extracted with five times their weight of water, dichloromethane and methanol (80%) at room temperature for 15 h. The filtrates were evaporated on a rotary evaporator (40 C) to yield the crude extracts. For the aqueous extracts, 10 g of powder in 250 ml distilled water were boiled during 15 min. Each of the extracts was lyophilized and weighed. The yield was 4.20, and 1.86 %, respectively, for the dichloromethane, methanol and aqueous extracts. Fungi cultures The antifungal activity of E. floribundus was evaluated against 8 strains of fungi, provided by the Medical Analysis Laboratory of Marseille (France). Seven of the strains were clinical isolates of the following dermatophyte species: Epidermophyton floccosum, Microsporum canis, M. gypseum, M. langeronii, Trichophyton mentagrophytes, T. rubrum and T. soudanense. One strain (Scopulariopsis brevicaulis) was an environmental filamentous fungus. Antifungal assay The antifungal activity was assessed according to the agar dilution method 12 on Sabouraud agar (Difco). Plant extracts were dissolved in dimethylsulfoxide and diluted to give serial twofold dilutions that were incorporated into growth medium. The Trop J Pharm Res, June 2008; 7 (2) resulting concentrations ranged from 2 to 0.06 mg/ml. Sabouraud agar plates were inoculated with 0.2 ml of a particular dermatophyte or fungi strain. The plates were incubated in duplicate over a period of 15 days at 30 C. The minimal inhibitory concentration (MIC), defined as the lowest concentration that produced no visible fungal growth after the incubation time, was recorded. RESULTS The antifungal activity of dichloromethane, methanol (80 %) and aqueous extracts obtained from Erigeron floribundus revealed that only the dichloromethane extract showed a good antifungal activity against the dermatophytes and filamentous fungus used (Table 1). The MIC values were 0.25 mg/ml against the strains of Epidermophyton floccosum, Microsporum gypseum, M. langeronii, T. rubrum, T. sudanense and S. brevicaulis. The extract was effective on Trichophyton mentagrophytes with MIC value of 0.5 mg/ml and exhibited a moderate activity against Microsporum canis, with MIC value of 1 mg/ml. No antifungal activity was observed for both methanol and aqueous extracts. DISCUSSION In the present study, Erigeron floribundus was investigated for its antifungal activity against dermatophytes and filamentous fungus. E. floribundus is a medicinal plant commonly used in traditional medicine in Côte d Ivoire as well as in other African countries to cure skin infections. The result indicated that the dichloromenthane extract was the most effective on clinical isolates of dermatophytes. This crude extract exhibited a broad spectrum antifungal activity with MIC values ranging between 1 and 0.25 mg/ml against Microsporum canis, M. gypseum, M. langeronii, Trichophyton mentagrophytes, T. rubrum, T. soudanense, Epidermophyton floccosum and Scopulariopsis brevicaulis. To the best of our knowledge, this is the first time the antifungal activity of E. floribundus has been reported against M. langeronii and T. soudanense, the most frequent dermatophytes causing dermatomycoses in Côte d Ivoire. In a previous screening of 100 plants from Rwanda 13 and 228 from Uganda 14 for their antimicrobial activity, the ethanol (80%) extract of E. floribundus was shown to display antifungal activity against Microsporum canis and Trichophyton mentagrophytes with a MIC of 500 mg/ml. Both methanol and aqueous extracts of E. floribundus did not exert antifungal activity against the fungi tested. Previous antifungal screening carried out by Tra Bi et al. 15 on several ivorian medicinal plants indicated that the same dichloromethane extract tested here was active on yeast while the methanol extract was not effective. This observation may be attributed to the nature of the biological active compounds. The antifungal activity observed for the dichloromethane extract suggests that the active metabolites of Erigeron floribundus are mostly lypophilic (dichoromethane). E. floribundus from Cameroon was chemically screened and yielded saponins, flavonoïds, tannins, phenols, alkaloids and essential oils 16. Among these compounds, the essential oils and flavonoids can be incriminated in the antifungal activity of E. floribundus. Some of these groups of compounds are lipophilic due to the presence of a prenyl chain. Therefore these components can be extracted by non polar solvents such as dichloromethane. The prenylated groups render the actives molecules more lipophilic inducing antimicrobial activity within interactions with cell membranes. This may probably explain the lack of activity observed with the polar (ethanol, methanol and water) extracts. However, there is a need to test the saponins, flavonoïds, tannins, phenols, alkaloids from E. floribundus for their antidermatophyte activity. CONCLUSION Our results offer a scientific basis for the use of Erigeron floribundus in traditional medicine in Côte d Ivoire for treatment of skin disorders. The dichloromethane extract of this plant showed promising antifungal activity against dermatophytes, some of which are the most frequent species implicated in 977 Table 1: Antifungal activity of Erigeron floribundus against dermatophytes (mg/ml) STRAINS EXTRACTS Dichloromethane Methanol (80%) Water Epidermophyton floccosum 0.25 nd nd Microsporum canis 1 2 2 Microsporum gypseum 0.25 2 2 Microsporum langeroniise 0.25 nd nd Trichophyton mentagrophytes 0.50 2 2 Trichophyton rubrum 0.25 nd nd Trichophyton soudanense 0.25 nd nd Scopulariopsis brevicaulis 0.25 nd nd nd = non determined dermatomycoses in Côte d Ivoire. This plant may also find application in veterinary medicine as some of the tested dermatophytes like Microsporum canis and Trichophyton mentagrophytes are zoophilic 17. A study is underway in order to identify the precise actives principles and understand the mode of action of E. floribundus. ACKNOWLEDGEMENT We are grateful to the Egide agency, the Government of France (Foreign Affairs Ministry) and the University of Mediterranee (Marseille) for financial support of this research. We acknowledge the technical support from staff Pharmacognosy, Botany and Cryptogamy laboratories. We warmly thank Professor Aké Assi Laurent and the Director of the National Centre of Floristic for botanical authentication and supply of plants. REFERENCES 1. Midgley G, Clayton YM, Hay JR. Atlas de poche de mycologie, Paris, Médecine-Science, Menan EIH, Zongo-Bonou O, Rouet F, Kiki-Barro PC, Yavo W, N'Guessan FN, Koné M. Tinea capitis in schoolchildren from lvory Coast (western Africa). A cross-sectional study. Int J Dermatol 2002; 41: ONUSIDA. Maladies opportunistes liées au VIH: Actualisation ONUSIDA, Genève (Suisse), Collection Meilleures Pratiques de l'onusida OMS. 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